In conventional color electrophotography a series of electrostatic images are created on an image member. The images are toned with different colored toners and then transferred in registration to a receiving surface to create a multicolor toner image. Typically, the receiving surface is a receiving sheet of paper or similar material which has been secured around the periphery of a transfer drum. The transfer drum is rotated in contact or near contact with the image member to repeatedly bring the receiving sheet into transfer relation with the consecutive images to overlay them in registration.
The photofinishing business worldwide thrives on a few commonly desired sizes of prints. In the United States, for example, nearly all prints are either (in inches) 4.times.6, 5.times.7, 8.times.10, or 11.times.17. Nearly all photofinishing operations produce many more of the smallest size (4.times.6) than of all of the larger sizes put together. However, some flexibility is necessary in all machines that are not dedicatd 100% to snapshots.
In silver halide photofinishing, this flexibility is supplied by supplying photographic paper in roll form, exposing and processing whatever pictures and whatever sizes are programmed into the printer and then cutting the prints to size later. It is known to cut the photographic paper both across the direction of movement and with the direction of movement so that some prints can be exposed side-by-side. Although a machine 100% dedicated to snapshots, for example, 4.times.6, may use either 4-inch wide or 6-inch wide rolls, it is more common to mix sizes on the same larger roll and custom cut. For example, 8-inch wide paper can be used for two rows of 4.times.6 images or one row of 8.times.10 images with both sets of images being positioned with their long dimension running with the direction of movement of the paper. All the 4.times.6's can be batched and the cutter set to cut 4.times.6's and then all of the 8.times.10's batched and the cutter repositioned for cutting 8.times.10's. The slitting and cutting art is sophisticated. Virtually any arrangement can be done automatically.
In electrophotography, all commercial color systems require the use of cut sheets. That is, a single cut receiving sheet is positioned around a transfer roller by attaching both its leading edge and its trailing edge to the roller. The roller is rotated through a nip with a toner image carrying image member once for each color image to be transferred.
If cut sheets are attached by both the leading and trailing end to a transfer roller and the apparatus is flexible enough to take sheets of different length, larger sheets will necessarily overlap the trailing end securing means of the shorter sheets. This presents a problem to transfer in these areas that has not been 100% solved for highest quality imaging. That is, vacuum holes under a sheet in a transfer nip in which transfer is done either by electrostatics or by heat affects the transfer enough to be noticeable in the image itself. Gripping fingers create even more noticeable artifacts.
Electronic electrophotographic imaging, for example, imaging by exposing a photoconductive image member with a laser or LED printhead, has added new flexibility to electrophotography and other similar systems. For example, U.S. Pat. No. 4,706,099 shows an electrophotographic copier in which a photoconductor having a width in excess of 16 inches scans a wide image fully across the photoconductor. When narrower images are desired, image information in memory is rasterized in a manner that causes the images to be scanned in pairs side-by-side across the width of the photoconductor. The images are transferred side-by-side to separate sheets stored on a roll and cut prior to transfer. Because it is a single color machine, the problem of a transfer roller holding sheets of different size is not faced.
This patent illustrates the capability present in the art to store image information in memory, retrieve it and place it at any desired location and orientation (portrait or landscape) desired on an image member such as a photoconductor. See also, for example, U.S. Pat. No. 4,408,301. In fact, electronic copiers and printers are available which allow the operator to pick the position, orientation and magnification of any stored image and place more than one image on the same final print.